This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Our experiments aim to evaluate the effect of ICG-PDT on mouse window chamber vasculature (an animal model which simulates PWS vasculature). Specifically, we are interested in determining the level of vascular shutdown achieved with ICG-PDT. Mice will receive ICG followed by laser irradiation. ICG will be injected retroorbitally allowing the ICG to diffuse into the bloodstream. Following a 1-minute delay, the epidermal side of the skin-fold will be irradiated with a GentleLASE 755 nm alexandrite laser;pulse duration and spot size will be 3 ms and 10 mm respectively. Mice will then be exposed to radiant exposures of 30, 40 or 50 J/cm2.